Figure 11.

Electronic break junction can be used to quantify the conductance of single molecules. As a gold contact is slowly broken, quantized decreases in conductance are observed, first corresponding to changes in the geometry of the gold contact (a,b), then a set of smaller quantized peaks (c,d) resulting from one, two, or three conductive molecules (here dipyridine) bridging the junction. At slightly larger distances, the junction ceases to exhibit conductance (e,f). Adapted from ref (164).